VEGGIES: Preheat the oven to 425º F. Add the broccoli and cabbage to separate baking sheets, toss with avocado oil, salt, and pepper to taste, and roast for about 20 minutes, stirring halfway through, until crispy.
SHRIMP: Pat the shrimp dry with a clean kitchen towel. Heat a dash of sesame oil in a large pan over medium-high heat. When hot, add the garlic, ginger, and red pepper flakes and cook for one minute, until aromatic. Add the shrimp, season with salt and pepper, and sauté until the shrimp are pinkish and opaque. Remove from heat.
NOODLES: Cook the noodles according to the package instructions, then drain and rinse thoroughly. Add to a large mixing bowl or saucepan along with the cooked veggies and shrimp.
PEANUT SAUCE: Whisk together the peanut butter, soy sauce, honey, lemon juice, water, and sesame oil until thin and smooth. Coat the noodles and toss to combine.
SCALLIONS: Use kitchen scissors to cut thin slices of scallion over the noodles. Toss gently to combine and serve right away.